1. Field of the Invention
The field of the invention relates to assemblies for aspirating tissue from the body through the use of a syringe.
2. Brief Description of the Related Art
Various aspiration devices have been designed for obtaining tissue samples and other liquid samples. Many such devices include modified syringe assemblies. U.S. Pat. Nos. 2,369,304; 3,835,835; 4,248,225; 4,664,128; 4,711,637; and 4,758,232 disclose a number of aspiration devices which employ syringes. U.S. Pat. No. 2,369,304 discloses a ratchet and pawl assembly which maintains a piston in a selected position within a syringe barrel, thereby providing a desired vacuum within the barrel.
It is often desirable to be able to aspirate tissue using only one hand. This allows the other hand to be used for other purposes. U.S. Pat. Nos. 4,664,128; 4,664,908 and 3,819,091 disclose two different constructions which allow syringes to be employed in this manner.